| 1. |
- Wang, Haichao, et al.
(author)
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Heat-power peak shaving and wind power accommodation of combined heat and power plant with thermal energy storage and electric heat pump
- 2023
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In: Energy Conversion and Management. - : Elsevier Ltd. - 0196-8904 .- 1879-2227. ; 297
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Journal article (peer-reviewed)abstract
- Wind power curtailment becomes a major problem in many countries. The wind accommodation mechanisms and energy saving potentials for the combined heat and power plant with thermal energy storage, electric heat pump and both should be evaluated more systematically and accurately to accommodate more wind power. Heat-power peak shaving capacities for thermal energy storage, electric heat pump and both are analyzed using a graphical method, while the operation strategy is proposed to maximize wind accommodation. A simulation model for wind power accommodation considering the energy balances and constraints of all production units is developed based on EnergyPRO. A regional energy supply system in Jilin Province, China is selected as the case study, where the influences of different peak shaving technologies and their parameters on the wind accommodation and energy saving are studied. The wind curtailment ratio is reduced from 20.31% to 13.04% and 7.51% with thermal energy storage and electric heat pump respectively, and it is further reduced to 4.21% with both. Systems with electric heat pump can save energy from 1.1% to 5.8% with different parameters of the peak shaving devices. It was found that electric heat pump has better accommodation capability than that of thermal energy storage. Wind accommodation can be improved by adding thermal energy storage to electric heat pump, but the effect gradually decreases as the storage size increases. Electric heat pump can increase the system’s energy efficiency, but it is not always energy efficient by adding thermal energy storage to electric heat pump. In fact, thermal energy storage should not be too large, otherwise the system’s energy efficiency will be reduced.
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| 2. |
- Wang, Haichao, et al.
(author)
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Study on the performance of a forced convection low temperature radiator for district heating
- 2023
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In: Energy. - : Elsevier Ltd. - 0360-5442 .- 1873-6785. ; 283
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Journal article (peer-reviewed)abstract
- Low temperature district heating has significant advantages in energy efficiency, but a huge amount of existing radiators lack the capabilities for low-temperate heating. The innovation of this study is to develop an optimal and techno-economic method to improve the heating power of existing radiator by mounting a small fan considering different hydraulic connection modes. An experimental test rig was designed to study the optimal installation positions and angles of the fan. For a dormitory room in China, a computational fluid dynamics (CFD) model was developed and verified. The model was used to determine the lowest supply temperature of the radiator. Results show that the fan should be placed in a position and angle that blows air over the hottest surface of the radiator i.e. the hot center. The lowest supply temperatures before and after installing the fan are 42.3 °C and 39.5 °C. The response speed is increased by 28%, stability time is shortened by 13%, while the maximum indoor temperature difference is reduced by 15% and the maximum indoor air velocity is reduced by 0.07 m/s. Payback time is 63 days for case study, indicating a good economic feasibility. The method is beneficial to both the heat plant and users.
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| 3. |
- Wang, Xiaolin, et al.
(author)
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Elevated CO2 effects on Zn and Fe nutrition in vegetables: A meta-analysis
- 2024
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Conference paper (peer-reviewed)abstract
- The atmospheric carbon dioxide (CO2) concentration has been progressively increasing since the onset of the Industrial Revolution and has already reached at around 420 μmol mol⁻¹ nowadays. It is well recognized that elevated CO2 concentration stimulates the yield for C3 crops, but it also simultaneously changes the essential nutrients. However, compared with the main crops, far less attention has been devoted to the effects of elevated CO2 concentration on vegetable growth and quality. Vegetables are highly recommended in daily diets due to their diverse range of beneficial compounds, such as vitamins, antioxidants, minerals, and dietary fiber. In controlled greenhouse vegetable cultivation, elevated CO2 has been widely adopted as an agricultural practice for enhancing plant growth. Thus, understanding both vegetable growth and nutrient status is crucial to assess the potential impacts of elevated CO2 on future food security in both natural and controlled environments. However, much more attention has been paid to biomass enhancement, and elevated CO2 effects on nutrient quality are less recognized. Among the nutrients, Zinc (Zn) and Iron (Fe) are essential elements in humans. Previous studies have demonstrated a decreasing trend of Zn and Fe in main crops such as wheat and rice with increased CO2, while less is known about whether this alleviation effect on Zn and Fe can apply to vegetables. Therefore, a meta-analysis was conducted in this study to evaluate the influence of elevated CO2 concentration in the atmosphere on vegetable Fe and Zn status, and quantify the potential impact of future climate on nutrition security.
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| 4. |
- Zhu, Yanji, et al.
(author)
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Nano SiC enhancement in the BN micro structure for high thermal conductivity epoxy composite
- 2021
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In: Journal of polymer research. - : Springer. - 1022-9760 .- 1572-8935. ; 28:10
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Journal article (peer-reviewed)abstract
- Improving the heat dissipation efficiency of electronic products is the key to the design of many modern electronic and mechanical systems. Herein, we combined the 3D network fabricating with the way of micron-nano reinforcement to prepare high thermal conductivity and excellent thermal stability composites. Epoxy resin was used as the matrix, while the silicon carbide foam (f-SiC) as skeleton and the BN/nano-SiC as thermally conductive fillers. The thermal conductivity of the EP/f-SiC/BN/nano-SiC composite reaches 3.5 W·m− 1·K− 1, which is about 16.6 times higher than that of pure epoxy resin. The characterization results of TC and infrared thermography images indicate that the EP/f-SiC/BN/nano-SiC composite possess superior heat transport performance. Meantime, the EP/f-SiC/BN/nano-SiC composite have excellent thermal stability, the THRI of EP/f-SiC/BN/nano-SiC reaches 195.8℃, which is 21.3℃ higher than that of pure EP. This work would provide a new strategy for improving the TC of polymers by using other 3D skeletons and micron-nano fillers, and is conducive to the development of high thermal conductivity and excellent thermal stability materials.
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